There is a program that allows capturing the output from another
program. It is called vsound and you can get it at
http://www.zip.com.au/~erikd/vsound/ I hope this will prove useful to
some of you. It doesn't replace a real "loopback device" BTW as it
grabs the output before it ever reaches /dev/dsp, and so couldn't grab
the mix formed by the output of several programs, but it does the job
for single data captures nevertheless.